Ethoxylated alkylphenol and alkyl carbonate fire extinguishing composition



United States Patent Office Patented Nov. 17, 1970 US. Cl. 252-3 3Claims ABSTRACT OF THE DISCLOSURE An improved fire-fighting compositionof an ethoxylated alkylphenol and an alkyl carbonate of the formula:

Where R is hydrogen or a methyl group has been discovered. This improvedfire-extinguishing composition is useful as a wetting agent, emulsifyingagent, low-expansion or high-expansion foam and performs exceptionallywell in the presence of both fresh and salt water.

BACKGROUND OF THE INVENTION The problem of extinguishing fires hasplagued mankind throughout recorded history. Today in sophisticatedsociety many improvements have been made and are being made to combatthis age-old problem. With increased industrialization and particularlythe exploitation of petroleum resources through petrochemicals, thescience and art of fire extinguishing has become quite sophisticated.Fires have now become classified into various categories which varyaccording to the material involved and according to the mode ofextinguishing a fire involving this material.

Our invention relates particularly to Class A and Class B materials.Class A materials, or ordinary combustible solids, include things likewood, cotton, paper, etc. Class B materials, or flammable liquids,include liquids such as gasoline, hexane, benzene, other aromatics andother liquid flammable hydrocarbons. Of special interest are the variouspolar solvents such as acetaldehyde, methyl ethyl ketone,Z-ethylhexanol, and the like. These polar solvents have previously beenextremely difficult, if not impossible, to extinguish when burning.

Many method of extinguishing fires and fire extinguishing compositionshave been explored by those interested in fire safety. Varied methodshave been used such as water alone, particularly for the Class A typefire mentioned above. In addition, dry chemicals have been used inattempts to extinguish many Class B fires. In attempts to smother thefires many of these dry chemicals are used as foams produced by mixingtwo chemicals such as aluminum sulfate and sodium bicarbonate, whichcontain a foaming agent and a stabilizer.

Another method which has been often used in fighting Class B fires iswith mechanical foam solutions Where the foam is made with liquidinducted into the water stream before it comes into contact with air toform the foam. These mechanical-type foam liquids or fire-extinguishingcompositions are generally classified as protein and syntheticcompositions.

The protein concentrate usually contains a high molecular weight topolypeptide formed by the chemical hydrolysis of vegetable or animalproteins from which it is made. Various metallic salts are included withthese protein liquids to give strength to the foam bubbles in thepresence of heat and the foam-forming mechanical action itself. Proteinfoams by and large base their fire-extinguishing ability upon theformation of a thick blanket of foam which smothers the fire. Proteinfoams are generally classified as a low-expansion foam. The variousexpansion-type classifications will be discussed hereinafter.

The synthetic mechanical foams are produced from concentrates whichcontain compounds of various types of synthetic detergents and arecapable of rapid foam formation in suitable foam-generating equipment.While there are several synthetic-type concentrates and compositions 0nthe market, it is generally necessary to maintain supplies of more thanone concentrate in order to have a fire-fighting capability against allof the various types of fires. Additionally, each of thesedifferent-type synthetic concentrates requires specialized equipment forthe use thereof depending upon whether it is high expansion, mediumexpansion, low expansion, an emulsification agent or a wetting agent.Thus, an installation, to have fire-fighting capability against a broadrange of flammable hazards, must purchase various types of firefightingmaterial and a variety of equipment with which to use this specializedmaterial.

It has been found that most of the commercially available mechanicalfoam materials, both protein and synthetic, are substantiallyineffective in fighting fires where polar solvents are involved.Accordingly, many fire-extinguishing concentrates are sensitive toWhether they are used with salt water or fresh water. This is importantwhen it may be necessary to extinguish a dockside or shipboard firewhere a flammable water immiscible liquid is involved.

As hereinbefore mentioned, the fire-fighting compositions arecategorized according to various classifications of material. Variousfire-fighting compositions are generally called wetting agents,emulsifying agents, low, high or medium-expansion foams. A wetting agentis generally used when fighting a Class A fire to improve the soakingcharacteristics of the water coming in contact with the flammablematerial.

An emulsifying agent is used in fighting a flammable liquid fire andacts to combine with some of the flammable material and emulsify it,thus producing a film of some sort on the burning material.High-expansion foams are those which produce a foam of a volume betweenand 1000 times that of the liquid used in fighting the fire.Medium-expansion foams generally range from about 10 times to 100 timesthe volume of the liquid and those below a ratio of 10 to l are known aslow-expansion foams.

In copending application Ser. No. 561,342, filed June 29, 1966, and nowabandoned, it was disclosed that a burning liquid fire could beextinguished by applying to the burning liquid a foam produced bypassing through an air expansion nozzle a mixture of water with 2 to 6volume percent of a nonionic surfactant having the formula R-O(CH CHO),,H wherein R was selected from the class consisting of alkyl groupscontaining from 4 to about 20 carbon atoms and alkylphenyl groupswherein the alkyl chain contains from about 4 to about 15 carbon atomsand n is a number of from about 4 to about 30. This material, thoughacceptable for extinguishing burning liquid fires in certaincircumstances, has some inherent disadvantages. It was found that smallamounts of water introduced into this concentrate caused gelation whichrendered the concentrate totally unusable for fire fighting. Theresulting gelation makes the material useless for further fireprotection. As was also disclosed in the copending application, thenonionic surfactant had a rela- 3 tively high freezing point. Eventhough ethylene glycol was added thereto to reduce the freezing point tousable temperature, the gelation problem still remained.

In some instances, viscosity not necessarily caused by gelation proved aproblem which impaired the efiective ness of the eduction of theconcentrate into the water stream.

Accordingly, it is an object of our invention to provide a fire-fightingcomposition which is adaptable for the eX- tinguishment of Class A andClass B fires.

It is a further objective of our invention to provide a fire-fightingcomposition which is useful either in salt or fresh water.

It is a further object of our invention to provide a firefightingcomposition which will be useful over a broad spectrum of applicationsfrom wetting agent through highexpansion foam.

It is a further object of our invention to provide a firefightingcomposition which does not gel when contacted with a small amount ofwater.

It is a further object of our invention to provide a firefightingcomposition which produces a foam stable under conditions where it issubjected to an overhead water spray.

Further objects and advantages of our invention will be apparent tothose skilled in the art upon reading the description which follows.Such objects and advantages are intended to be included within the scopeof our invention.

SUMMARY OF THE INVENTION Our invention relates to an improvedfire-fighting composition which is useful as a wetting agent,emulsifying agent or as an expanded foam in fighting Type A and Type Bfires, including polar solvent fires, and the method of fighting saidfires with our improved fire-fighting composition. More particularly,this invention is directed to an improved fire-fighting composition madeup of a solution of an ethoxylated alkylphenol having the formula:

@owmomonn where R is a C to C alkyl group and m has an average value offrom 4 to about 30.

This ethoxylated alkylphenol is mixed with an alkyl carbonate of theformula:

RI Ht'l-O wherein R is hydrogen or a methyl group in such pro portionsthat the carbonate is present in the amount of about 0.1 to about 0.75part of weight per part of the ethoxylated alkylphenol.

The method of extinguishing fires involves incorporating the improvedfire-fighting composition of our invention into a water stream andexpelling the water stream to contact the burning material. If it isdesired to use the fire-fighting composition as a wetting agent oremulsifying agent, it is expelled along with water through a standardnozzle which does not produce an expanded foam.

When expelled through a nozzle which introduces air into the liquidstream, an expanded foam results and is applied to the burning material.The fire-fighting composition is introduced into the water stream suchthat it makes up about 0.5 to about 6 volume percent of the aqueoussolution depending upon the type of fire involved and the classificationof use; i.e., wetting agent or expanded foam. Wetting agents are usuallyapplied to burning materials at the lower concentrations whereas thefoamed material generally requires higher concentrations.

4 DESCRIPTION OF THE INVENTION Our invention involves a fire-fightingcomposition adaptable to a broad spectrum application to various typesof fires, including Class A fires of combustible solids and Class Bfires of flammable fluids, which include the hard to extinguish polarsolvent fires.

While other special purpose additives may be present, our improvedfire-fighting concentrate is essentially a twocomponent system which isblended together to form a homogeneous solution. One component is anethoxylated alkylphenol having the general formula:

Q-owmomonn where R is a C to C alkyl group and it has an average valueof from 4 to about 30.

The other essential component is an alkyl carbonate of the formula:

wherein R is hydrogen or a methyl group. This alkyl carbonate isgenerally present with the ethoxylated alkylphenol in an amount of about0.1 to about 0.75 part of weight of the carbonate per part by weight ofthe ethoxylated alkylphenol. It is especially preferred to use propylenecarbonate as the alkyl carbonate.

While this is essentially a two-component composition, it is alsopermissible to include in the concentrate a foam stabilizer such as highmolecular weight polymers of ethylene oxide, polyvinyl resins,polyglycols, and the like. The use of these materials is described inU.S. Patent 3,25 8,423. An especially effective foam stabilizer has beenfound to be 2000-4000 molecular weight polyethylene glycol. As taught bythe aforementioned patent, these additives are included in an amount inthe range of from about 0.5 to 5 wt. percent of the concentrate. It iswithin the scope of our invention to include in our fire-fightingcomposition this additive as long as the above two components, i.e., thealkyl carbonate and the ethoxylated alkylphenol are present in theproportions hereinabove mentioned.

In preparing and storing the concentrate of our invention, it is best tokeep it as nearly anhydrous as possible since the presence of excessivewater causes a hydrolyzation of the propylene carbonate. Slight amountsof water, however, do not cause excessive problems such as caused to theethoxylated alkylphenol or the mixture of it with ethylene glycol whenonly slight amounts of water are present.

The use of this improved fire-fighting composition is not limited to anyone particular aspect, but is equally applicable to use as a wettingagent in fighting fires of Class A substances such as wood, mattresses,textiles, cotton and other combustible solids.

It is also applicable for use as an emulsifying agent to act uponflammable fluids to form a thin emulsion layer on the top thereof. Andit is also useful in forming low, medium or high-expansion foams forfighting fires of Class B flammables such as aromatic distillates,benzene, toluene, xylene, gasoline, kerosene, fuel oil, jet fuel,hexane, heptane, octane, and the like. We have also discovered it to beparticularly useful in fighting previously very difiicultly extinguishedfires involving polar solvents such as acetaldehyde, benzaldehyde,methyl ethyl ketone, ethyl acetate, butyl acetate, and the like.

In addition, our fire-fighting composition is useful even in thepresence of salt water and extinguishes fire particularly difficult tocontrol, such as the polar solvents and hexane. This is true even whenthe fire occurs in the presence of flashback hazards such as metalstructures present in the burning fluid.

Our foam has also proved to be stable when used in conjunction withwater deluge sprays. This situation often occurs when a flammable liquidbecomes ignited in a chemical plant or petroleum refinery or around astorage tank containing flammable fluids. Deluge sprays, whileineffective to extinguish the fire itself, are used to keep thestructural metal from reaching a temperature at which its structuralstrength fails. Prior art foams have been found to disintegrate badlyunder a water deluge spray system.

The fire-fighting composition of our invention has been found to benongelling upon contact with minor amounts of water. The importance ofthis improvement is quite apparent.

In addition to prohibiting the gelation of the ethoxylated alkyl phenol,the alkyl carbonate also reduces the viscosity of the concentrate atlower temperatures. For example, a concentrate of 60% nonylphenol adductwith about 9.5 mols ethylene oxide and 40% propylene carbonate has thefollowing viscosity in centistokes 270 at F., 140 at F. and 60 at 60 F.

Unlike many fire-fighting compositions, particularly the protein typematerial, our improved fire-fighting composition does not deteriorateupon standing in storage nor does it present corrosion problems to thefire-fighting system in which it is to be used.

Our invention will be further illustrated by the following exampleswhich are intended to be merely for purposes of illustration and not tolimit the scope of our invention.

EXAMPLE I Into a test pit having approximately 1,000 square feet areawas introduced 120 gallons of an aeromatic distillate having a flashpoint of 20 F., initial boiling point of 115 R, an end point of 165 F.,and a Reid vapor pressure of 7 p.s.i. This material was ignited andallowed to burn for one minute. Then through a standard 200 gallon perminute fog nozzle water was used to attempt to put out the fire. Aftertwo minutes the fire was still not extinguished and was allowed to burnitself out.

EXAMPLE II Example I was repeated except that the fire was extinguishedin seconds, using the same fog nozzle but applying a fog using aconcentrate of the 9 /2 mol adduct of ethylene oxide with nonylphenoland 20% propylene carbonate educted into the water stream through anational Aer-O-Foam LP17A eductor, which was rated EXAMPLE III Twohundred and twenty gallons of JP4 jet fuel was placed in the 1,000square foot pit, ignited, and allowed a one-minute preburn. The 80%nonylphenol-9.5 mol ethylene oxide adduct and 20% propylene carbonateconcentrate was applied to the fire using the eductor used in Example IIthrough a National Aer-O-Foam PC31 fog nozzle and extinguished the firein 47 seconds.

EXAMPLE IV A fire using fuel oil having a flash point less than R, aninitial boiling point of 98 R, an end point of 625 F., and a IReid vaporpressure of 11 p.s.i. was ignited as in Examples II and III. The eductorand concentrate of Example HI and a Rockwood sprinkler Model CF-6200nozzle rated at 250 gallons per minute was used to extinguish this firein 42 seconds.

EXAMPLE V Another fire was built in the 1,000 square foot pit using JP-4jet fuel and allowed a one-minute preburn.

Using the eductor rated at 3% described in Example II, the /20%concentrate of Example II was applied to burning fluid through a foamapplicator which produced the foam and flowed it on to the burning fluidsurface at one edge of the fire at a water rate of 200 gallons perminute. After one minute and 43 seconds the foam covered the pit and thefire was extinguished.

EXAMPLE VI In a rectangular pit having a fuel area of square feet wasplaced gallons of methyl ethyl ketone, a polar solvent. The fuel bed, 2"deep, was ignited and allowed a 15-second prehurn. The foam was appliedusing the eductor of Example II and the foam applicator described inExample V to apply the 80% nonylphenol 9.5 mol ethylene oxide adduct,20% propylene carbonate concentrate at the edge of the fire pit. Thisfire was extinguished in 1 minute and 53 seconds.

The foam surface over the fuel was broken and the fuel was reignited.This was extinguished by pushing the foam back over the fire with awater fog. This further demonstrates the stability of the foam in thepresence of an overhead water spray and the difficulty at which theflammable liquid may become reignited and spread to cause damage afterthe fire was considered to be extinguished.

From the aforegoing description and discussion of our invention, itwould be apparent to many skilled in the art how successful modificationof the same may be made. It is our intention that these modificationsand changes of our invention are within the scope of our invention andcovered by the claims hereby appended.

We claim:

1. An improved fire-fighting composition useful as a wetting agent,emulsifying agent or as an expanded foam, consisting essentially of aconcentrate solution of an ethoxylated alkyl phenol and an alkylcarbonate having about 0.1 to about 075 part by weight of the alkylcarbonate per part of the ethoxylated alkyl phenol wherein theethoxylated alkyl phenol is represented by the formula:

Q-owrncrnonu and the alkyl carbonate is represented by the formula:

R1 HJ 0 and R is a C to C alkyl group, R selected individually, ishydrogen or methyl and n has an average value from 4- to about 30.

2. The composition of claim 1 wherein R is a C alkyl group and n has anaverage value of 9.5.

3. The composition of claim 2 wherein the alkyl carbonate is propylenecarbonate.

References Cited UNITED STATES PATENTS 2,088,085 7/1937 Gross et al252-351 2,529,211 11/1950 Busse et al 252-3 3,008,905 11/1961 Wedell252307 JOHN T. GOOLKASIAN, Primary Examiner D. I. FRITSCH, AssistantExaminer US. Cl. X..R.

